This invention relates to a process for adjusting the cis-trans double bond configuration in polyalkenamers produced by ring-opening polymerization.
Cyclic olefins having at least one unsubstituted ring double bond can be conventionally polymerized with the aid of so-called metathetic catalysts with ring opening (DOS's Nos. 1,570,940; 1,645,038; 1,720,798; 1,770,143; and 1,805,158; DAS No. 1,299,868; British Patent Nos. 1,124,456; 1,194,013; and 1,182,975).
It is furthermore known that open-chain monoolefins act as molecular weight modifiers in the presence of the metathetic catalysts during the polymerization of cycloolefins (DOS No. 2,922,335 and German Patent Nos. 1,919,047; 1,945,358; 2,027,905; 2,028,716; 2,028,935; 2,105,161; and 2,157,405), and as degrading agents on polymers the main chain of which contains unsubstituted double bonds (DOS No. 1,929,140 and U.S. Pat. No. 3,558,589).
Normally, the double bonds in the products (polyalkenamers) obtained by ring-opening polymerization--optionally with addition of a molecular weight modifier--are predominantly of the transconfiguration. Thereby the thermoplastic character predominates, rather than the frequently desired elastomeric character.